Unravelling the unique roles of NCQDs over CeFeO3 perovskite as highly efficient photoluminescent solar induced peroxymonosulfate/photocatalyst system: Optimization of removal process, mechanism and degradation pathway

In this work, novel ferrite type CeFeO3 perovskite was elaborately designed with nitrogen-doped carbon quantum dots (NCQDs) for effective degradation of ciprofloxacin (CPX) under peroxymonosulfate (PMS) activated photocatalytic system. The critic roles of NCQDs addition in the PMS-activated system were examined through characterization and photocatalytic tests. The as-fabricated CeFeO3 @NCQDs heterojunction showed superior catalytic performance (92.5 %) which was 2.8 times higher than that of bare CeFeO3 (32.0 %). It was found through XPS analysis that new oxygen-rich bonds were formed in the CeFeO3 @NCQDs sample, providing new reaction sites. PL technique showed that the carrier separation efficiency of the composite was significantly superior to that of the sole CeFeO3 due to excellent electron transfer property of NCQDs. Furthermore, the change in the band energy potentials improved the oxidation ability, resulting in increased degradation rate. The heterojunction catalyst also showed high removal efficiency in real water matrices. Meanwhile, radical trapping tests showed that the superoxide radicals play dominant roles in the photodegradation system. The as-synthesized catalyst also exhibited satisfactory performance in dye decomposition reactions. In addition, Box–Behnken design was applied to find out the optimum conditions which were determined as catalyst dosage of 0.80 g/L, PMS concentration of 4.90 mM and initial CPX concentration of 7.00 mg/L. The CeFeO3 @NCQDs/Vis/PMS system could be considered as a promising candidate in the aspect of practical wastewater treatment applications.